Today, in WCDMA (Wideband Code Division Multiple Access), packet-data traffic is often bursty with occasional periods of transmission activity. From a user perspective it is advantageous to have the HS-DSCH (High-Speed Downlink Shared Channel) and the E-DCH (Enhanced Dedicated Channel) configured to quickly be able to transmit user data. Simultaneously, maintaining the connection in uplink and downlink comes at a cost. From a perspective of the network, there is a cost in uplink interference even in absence of data transmission. From a UE (user equipment) perspective the power consumption is a main concern, even when no user data is received since the UE still needs to transmit on e.g. the DPCCH (Dedicated Physical Control Channel).
To reduce UE power consumption, WCDMA has several RRC (Radio Resource Control) states, such as URA_PCH (URA Paging channel), CELL_PCH (Cell Paging channel), CELL_FACH (Cell Forward access channel) and CELL_DCH (Cell Dedicated Channel), which are all known and described in the prior art. RRC signaling is typically used for moving the UE between the different states.
The lowest power consumption is achieved when the UE is in one of the states URA_PCH and CELL_PCH. Then the UE sleeps and is only occasionally activated to check any paging message. For exchange of user data the UE needs to be moved to the CELL_FACH or CELL_DCH states.
When the UE is in the CELL_FACH state it can transmit some amounts of user data, and the UE monitors common downlink channels for small amounts of user data and RRC signaling. Also, in the CELL_FACH state power consumption is higher than in the URA_PCH or CELL_PCH states, but lower than in the CELL_DCH state. In the CELL_DCH state the UE can transmit the relatively highest amount of user data and/or have the smallest delay, but the power consumption of the UE is then also the highest.
Hence, as implied above, from a transmission/delay perspective it is preferable to keep the UE in the CELL_DCH state. However, one of the states URA_PCH and CELL_PCH is preferred if interference, system resource consumption and/or UE power-consumption should be reduced.
The communication network that the UE is part of, as well as the UE per se, are affected by which state the UE is in, and a number of considerations must be done for obtaining a configuration that is optimal for the network and/or the UE. This issue is addressed e.g. in WO2009/099368 which discloses how a throughput parameter can be handled, and WO2009/082329 which discloses how release of common resources can be provided.
Thus, it still presents a problem to further improve the performance for both the communication network and/or the UE, while still employing and taking into account the requirements of one or more of the states URA_PCH, CELL_PCH, CELL_FACH and CELL_DCH.